1. Field of the Invention
The present invention relates to a solid-state image sensor, a method of manufacturing the same, and a camera.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2003-229551 describes a solid-state image sensor which has a planarizing film arranged on a semiconductor substrate including a photoelectric conversion region and pad portion, a color filter film arranged on the planarizing film, and an on-chip microlens arranged on the color filter film. An opening is formed in a layer of the on-chip microlens and the planarizing film so as to expose the pad portion.
In recent years, as a pixel size is reduced, an amount of light which enters each photoelectric converter is decreased. Hence, in order to enhance an intensity of light entering each photoelectric converter, an antireflection film is formed on the surface of a microlens. However, after an inorganic film which forms the antireflection film was formed on an organic film which forms the microlens, when the inorganic film and organic film were plasma-etched to expose the pad portion, an insulation breakdown phenomenon of the organic film was observed although it occurred at a very low probability. This insulation breakdown may damage the pad portion. According to experiments of the present inventors, it was revealed that the insulation breakdown of the organic film occurred immediately after the inorganic film was penetrated by plasma etching. The present inventors estimated that the insulation breakdown of the organic film was caused since a breakdown voltage of the organic film was much lower than that of the inorganic film, a resist pattern formed on the inorganic film was charged by plasma, and a high voltage was applied between the resist pattern and pad portion. More specifically, the present inventors estimated that a high voltage was applied to the organic film below the inorganic film at an instance when the inorganic film was penetrated, thus causing the insulation breakdown of the organic film, and damaging the pad portion below the organic film. Also, the same problem may be posed not exclusively for an antireflection film but when an inorganic film is formed on a microlens formed of an organic substance. As such example, the problem occurs, for example, when a protection film or a planarizing film for implementation is formed.